Heat-Strengthened Glass

Characteristics of the product

Heat-strengthened Glass is produced through the same procedure as tempered glass by using the same level of heat, yet it is slowly cooled down, hence tension of heat-strengthened glass is less than that of tempered glass. This makes it less strong and less durable towards temperature compared to tempered glass. Heat-strengthened glass has no weakness in terms of self-breakage like in the case of tempered glass as less tension occurred in the glass. Breakage will not be in grains but in bigger pieces, and its fracture will run towards the edge of glass instead. Even though the durability of heat-strengthened glass is less than tempered glass endurance, it is still can tolerate pressure and forces in the stage of adequate for glass fitting. Glass types that can be manufactured to heat-strengthened glass are similar to the kinds of tempered glass


  1. 2 times stronger than float glass, allowing it to be capable of withstanding crash, pressure, and squeeze.
  2. High-temperature resistance up to 290 ºC without breaking.
  3. Tolerates acute temperature changes up to 100 ºC.
  4. Its cracks will run into the edge of the glass when it’s broken. Number of cracks are handful, their cracks are larger than general glass and pieces of broken glass are large.
  5. No spontaneous breakage as the case of tempered glass.


  1. Heat-strengthened glass cannot be cut, pierced, and chipped off.
  2. As heat-strengthened glass has been exposed to high temperature during the production, the material becomes soft. Despite the fact that we exercise caution when moving glass inside the oven, there is still slightly wave and deflection. If required entirely smooth with no waves on glass such as the case of glass for photocopy machine, other types of glass are required.
  3. Heat-strengthened glass cannot substitute tempered glass due to less force reception towards crashing, pressing, and squeezing forces. The fact that heat-strengthened glass will break into large pieces could cause an unexpected severe harm in case there is no glass frame.


Heat-strengthened glass receives crashing, pressing, and squeezing forces better than ordinary glass. In some areas that are unnecessary to withstand high crashing, pressing, and squeezing forces, heat-strengthened glass is recommended in order to avoid spontaneous breakage of tempered glass. Glass selection should be made based on calculation whether heat-strengthened glass can withstand forces in that specific place or not since heat-strengthened glass can endure less forces than tempered glass does. Another concern is when it is broken due to unexpected causes, the glass will fall over and cause any severe dangers or not.


Thickness level that can produce heat-strengthened glass: 3, 4, 5, 6, 8, 10, 12 millimeters.


The smallest size that can be produced: 180 X 180 millimeters.


The largest size that can be produced: 2,800 X 6,000 millimeters.

* Remarks: The size of thin glass depends on raw materials; hence, please inquire about the size before ordering. 


Caution in use

  • Heat-strengthened glass cannot be cut, pierced, and chipped off after the production of manufactured into heat-strengthened glass. Thus, measuring areas carefully is necessary, and we encourage to use the unit of ‘millimeter’ for an accuracy. Allowing it to be slightly loose will enable to install glass easier, yet it shouldn’t be too loose to slip out of glass moldings.
  • A single piece of heat-strengthened glass should not be used for making a roof or a wall of high-rise buildings as it is possible to fall over in case glass is broken.
  • A single piece of heat-strengthened glass should not be applied for floor making, pedestrian areas, or staircase as people can fall down immediately when the glass is broken, and it can harm people down there as well.
  • The selection of using heat-strengthened glass instead of tempered glass requires thorough calculation of receiving forces along with a concern of an installment whether there will be any severe dangers or not.
  • Heat-strengthened glass cannot be used as a substitution for fire-proof glass since heat-strengthened glass cannot resist fire and provide safety for residents according to the restriction of fire-proof.

The way to detect a heat-strengthened glass

Heat-strengthened glass has the same issue in detection as tempered glass does, and it can be examined by using the same means. In case of smashing, heat-strengthened glass will break by having cracks running towards a glass frame with no small pieces around the center of breakage.

Using polaroid film can also be applied as it can enable us to see line of force that exists around the glass edge. This particular line of force can be seen in both heat-strengthened glass and tempered glass.